More Miami-Dade County Headlines

Frazer said the boy was playing with the loaded gun and shot himself in the head.

Police encouraged parents to properly secure their firearms and urged children not to touch firearms if they see them in the home.

"Such a tragedy that could have been avoided by simply locking up the firearm," Officer Carlos Austin said. "Gun ownership is a huge responsibility."

Officers cordoned off several blocks around the scene.

Reiner Perez, who was visiting his mother, said he was talking on the phone in his mother's backyard when he heard a single gunshot. Perez said then he saw a woman run from a nearby home, screaming for help.

Miami-Dade County Superintendent Alberto Carvalho called the shooting "heartbreakingly unacceptable and entirely preventable."

"Early reports confirm one of our 6-year-old students accidentally shot himself in the head; an older child witnessed it," Carvalho said on Twitter. "What will it take for adults to secure their guns? How much more heartache? When is it finally enough?!"

Paramedics airlifted the boy to Jackson Memorial Hospital in Miami, where he died.

A neighbor told Local 10 News how the child loved to play outside.

"It's very sad," she said. "We need to do something about it. What, I don't know."